unit1.pas

《delphi深度编程及其项目开发》

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TPersonRec = packed record
    Name: string[40]; //姓名
    BirthDay: TdateTime; //生日
  end;
  TForm1 = class(TForm)
    btnOpenRead: TButton;
    BtnWrite: TButton;
    Memo1: TMemo;
    procedure btnOpenReadClick(Sender: TObject);
    procedure BtnWriteClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.btnOpenReadClick(Sender: TObject);
var
  PersonRec: TPersonRec;
  DataFile: file of TPersonRec;
  i: integer;
begin
  //关联文件
  AssignFile(DataFile, 'PersonFile.dat');
  if not FileExists('PersonFile.dat') then
    raise Exception.Create('personFile.dat不存在');
  //打开文件
  Reset(DataFile);
  Memo1.Lines.Clear;
  try
    i := 1;
    while not Eof(DataFile) do
    begin
      //读到PersonRec记录中
      Read(DataFile, PersonRec);
      Memo1.Lines.Add('******第' + IntToStr(i) + '条记录********');
      Memo1.Lines.Add('姓名： ' + PersonRec.Name);
      Memo1.Lines.Add('生日： ' + DateToStr(PersonRec.BirthDay));
      i := i + 1;
    end;
  finally
    CloseFile(DataFile);
  end;
end;



procedure TForm1.BtnWriteClick(Sender: TObject);
var
  PersonRec: TPersonRec;
  DataFile: file of TPersonRec;
begin
  //关联文件
  AssignFile(DataFile, 'PersonFile.dat');
  //文件存在，就打开，否则创建
  if FileExists('PersonFile.dat') then
    Reset(DataFile)
  else
    Rewrite(DataFile);
  PersonRec.Name := '陈鹏';
  PersonRec.BirthDay := StrtoDate('1980-01-07');
  //移动文件指针到文件尾部
  Seek(DataFile, FileSize(DataFile));
  try
    //将PersonRec记录写入到文件中
    Write(DataFile, PersonRec);
  finally
    CloseFile(DataFile);
  end;
end;

end.